Mixed Conducting Ceramic Membranes (eBook)

Prof. Xuefeng Zhu received his PhD from the Dalian Institute of Chemical Physics, Chinese Academy of Sciences in 2006, and became a full professor at the same institute in 2014. His research interests include mixed conducting membranes for O2, H2 separation and production, cathode materials for intermediate-low-temperature solid oxide fuel cells, electrochemical oxygen reduction and evolution reactions for electrolyzing water and metal-air batteries, highly selective catalytic oxidation of light hydrocarbons to olefins, and catalytic oxidation reactions in inorganic membrane reactors. Prof. Zhu has published over 60 peer-reviewed scientific papers, H-index 24, has contributed to 2 book chapters, given more than 20 oral presentations at international and domestic conferences and workshops, and holds 11 patents. Prof. Weishen Yang completed his PhD on catalysis at the Dalian Institute of Chemical Physics, Chinese Academy of Sciences in 1990. After graduation, he started working at the same institute, and became a full professor in 1995. As a visiting scholar, he worked at the University of Birmingham (UK) in 1989 and University of Southern California (USA) in 2001. His research mainly focuses on the synthesis and application of inorganic membranes and new catalytic materials in solving energy related problems, which include (1) Alternative Energy: Oxygen permeable membranes for natural gas conversion; (2) Renewable Energy: Zeolite membranes for bio-fuel (ethanol/butanol)/water separation; (3) Clean Energy: Hydrogen permeable membranes for pure H2 production; (4) Advanced Energy: Hydrogen and/or oxygen permeable membranes used in solid oxide fuel cells (SOFC). Prof. Yang has produced over 280 refereed journal publications, 4 invited review articles, 4 book chapters, holds 40 patents and has given more than 30 invited lectures in academia and industry around the world.

Preface 6
Contents 8
Chapter 1: Introduction to Mixed Ionic-Electronic Conducting Membranes 13
1.1 Introduction 13
1.2 Principle of Oxygen Permeation 15
1.3 Types of Membranes 17
1.4 Scope of This Book 20
References 22
Chapter 2: Defects and Diffusion 23
2.1 Defects Concerned in MIEC Materials 23
2.1.1 Point Defects 24
2.1.2 Point Defect Notations 26
2.1.3 Electrons and Holes 27
2.1.4 Defects in MIEC Oxides 29
2.1.4.1 Fluorite-Type Ceria-Based Materials 29
2.1.4.2 Perovskite-Type Materials 30
2.1.5 Association of Defects 32
2.1.6 Equilibria of Defect Reactions 34
2.1.7 Grain Boundaries 43
2.2 Ionic Diffusion 47
2.2.1 Vacancy Diffusion and Interstitial Diffusion 48
2.2.2 Diffusion Path of Oxygen Ions 49
2.2.2.1 Fluorite-Type Oxides 49
2.2.2.2 Perovskite-Type and Related Oxides 52
2.2.3 Diffusion Coefficients 54
2.2.4 Diffusion and Ionic Conductivity 56
2.2.5 Grain Boundary Diffusion 58
References 58
Chapter 3: Ionic Conductors and Aspects Related to High Temperature 61
3.1 Fluorite-Type Oxygen Ionic Conductors 61
3.1.1 Zirconia-Based Ionic Conductors 62
3.1.1.1 Stabilization of Zirconia by Doping 62
3.1.1.2 Scandia-Stabilized Zirconia 65
3.1.1.3 Zirconia-Based Membranes for Oxygen Permeation 66
3.1.2 Ceria-Based Ionic Conductors 68
3.1.2.1 Doped Ceria 68
3.1.2.2 Co-Doped Ceria 70
3.1.2.3 Ceria-Based Membranes for Oxygen Permeation 71
3.1.3 Bismuth Oxide-Based Ionic Conductors 73
3.1.3.1 Structure of delta-Bi2O3 73
3.1.3.2 Doped Bismuth Oxide 74
3.1.3.3 Bi2O3-Based Membranes for Oxygen Permeation 77
3.2 Perovskite-Type Oxygen Ionic Conductors 78
3.2.1 Structure of Perovskite Oxides 78
3.2.2 Nonstoichiometric Oxygen 81
3.2.3 Critical Radius, Free Volume, and M-O Bonding Energy 82
3.2.4 LaGaO3-Based Pure Ionic Conductors 85
3.2.5 Perovskite-Type Mixed Ionic and Electronic Conductors 89
3.3 Other Ionic Conductors 89
3.3.1 La2Mo2O9 90
3.3.2 Bi4V2O11 91
3.3.3 La10-xSi6O26+y 92
3.4 Relevant High-Temperature Ceramic Materials 94
3.4.1 Cationic Diffusion 94
3.4.2 Kinetic Demixing 97
3.4.3 Thermal Expansion and Chemical Expansion 99
3.4.4 Creep 100
References 101
Chapter 4: Fabrication and Characterization of MIEC Membranes 106
4.1 Preparation of Ceramic Powders 106
4.1.1 Solid-State Reaction Method 107
4.1.2 Complexing Method 109
4.1.3 Coprecipitation Method 112
4.1.4 Spray Pyrolysis Method 115
4.2 Preparation of Membranes 118
4.2.1 Dry-Pressing 119
4.2.2 Extrusion 121
4.2.3 Slip Casting 124
4.2.4 Tape Casting 127
4.2.5 Phase Inversion 131
4.2.6 Other Methods 135
4.2.7 Comparison of the Methods 135
4.2.8 Sintering 135
4.3 Characterization of MIEC Membranes 139
4.3.1 Permeation Flux 139
4.3.2 Electric Conductivity 140
4.3.3 Nonstoichiometric Oxygen 142
4.3.3.1 Thermogravimetric Analysis 142
4.3.3.2 Iodometry 143
4.3.3.3 Coulometric Titration 144
4.3.4 Diffusion Coefficients and Exchange Coefficients 145
4.3.4.1 Isotope Exchange 146
4.3.4.2 Electrical Conductivity Relaxation (ECR) 148
4.3.4.3 In Situ Isothermal Isotope Exchange (IIE) 149
4.3.4.4 Oxygen Permeation 151
4.4 Structure and Morphology Characterizations 152
References 152
Chapter 5: Permeation Principle and Models 155
5.1 Introduction 155
5.2 Wagner Equation and Related Modifications 156
5.3 Jacobson´s Model 162
5.3.1 Model Development 162
5.3.2 Model Application 166
5.4 Xu and Thomson´s Model 168
5.4.1 Model Development 168
5.4.2 Model Application 172
5.5 Zhu´s Model 175
5.5.1 Model Development 175
5.5.2 Model Applications 182
5.5.2.1 Experimental Verification 182
5.5.2.2 Kinetic Parameters 184
5.5.2.3 Permeation Resistance Distributions 185
5.5.2.4 Degradation Mechanism Analysis 186
References 187
Chapter 6: Perovskite-Type MIEC Membranes 189
6.1 Perovskite Structure 189
6.2 Defect Chemistry in Perovskite Oxides 191
6.3 An Introduction to the Pioneering Works of Teraoka and Coworkers 192
6.4 Co-containing Perovskite Membranes 194
6.4.1 LnCoO3-delta System 194
6.4.1.1 Substitution in B Sites 194
6.4.1.2 Substitution in A Sites 195
6.4.1.3 Typical LnCoO3-delta-Based Perovskite Membrane Materials 196
6.4.2 (Ba,Sr)CoO3 System 199
6.4.2.1 SrCo1-xMxO3-delta 200
6.4.2.2 SrCo1-xFexO3-delta 203
6.4.2.3 BaCo1-x-yFexMyO3-delta 206
6.4.3 Ba0.5Sr0.5Co0.8Fe0.2O3-delta 208
6.4.3.1 Oxygen Exchange and Diffusion Kinetics 209
6.4.3.2 Oxygen Permeation 212
6.4.3.3 Phase Transformation 216
6.5 Co-free Perovskite Membranes 225
6.5.1 LaGaO3 System 226
6.5.2 BaFeO3-delta System 227
6.6 Perovskite-Related MIEC Membranes 228
6.6.1 Ruddlesden-Popper Series Materials 228
6.6.2 Other Types 230
References 231
Chapter 7: Dual-Phase MIEC Membranes 237
7.1 Introduction 237
7.2 Traditional Dual-Phase MIEC Membranes 238
7.3 New Type of Dual-Phase MIEC Membranes 240
7.3.1 Design of Dual-Phase Membranes with High Stability and Permeability 241
7.3.2 Comparison Between the Traditional and New Dual-Phase Membranes 245
7.3.3 Interfacial Oxygen Exchange 250
7.3.4 Microstructure Effects 254
7.3.4.1 Preparation Methods of the Composite Powders 254
7.3.4.2 Elemental Composition 261
7.3.4.3 Sintering Temperature-Induced Microstructural Effects 263
7.3.5 Ratio Between the Two Phases 268
7.3.6 Other Potential Factors 270
7.4 Outside/Inside Short Circuit 271
7.5 Asymmetric Dual-Phase Membranes 273
References 275
Chapter 8: Oxygen Permeation at Intermediate-Low Temperatures 280
8.1 Introduction 280
8.2 Difficulties Related to Oxygen Permeation at Intermediate-Low Temperatures 281
8.3 Degradation Mechanisms 282
8.4 Degradation and Stabilization Mechanisms of Phase-Stable Membranes 284
8.4.1 Sulfur-Containing Membranes 284
8.4.2 Silicon-Containing Membranes 288
8.4.3 Mechanism of Sulfur and Silicon Migration to the Membrane Surface 292
8.4.4 Stabilization of the Phase-Stable Membranes at Low Temperature 295
8.5 Degradation and Stabilization Mechanisms of Phase-Unstable Membranes 297
8.5.1 Degradation Mechanism of Ba0.5Sr0.5Co0.8Fe0.2O3-delta at Intermediate-Low Temperatures 297
8.5.2 Stabilization Mechanism of Ba0.5Sr0.5Co0.8Fe0.2O3-delta at Low Temperatures 302
8.5.2.1 Phase Transformation of BSCF at Low Temperature 302
8.5.2.2 The Attempts to Inhibit Phase Transformation by Light Doping in B Site 305
8.5.2.3 Nanoparticles Inhibiting Phase Transformation 306
8.5.2.4 Possible Mechanism 307
A Thermodynamic Analysis 307
A Kinetic Analysis 309
8.5.2.5 High Permeation Flux at Low Temperatures 311
References 312
Chapter 9: Catalytic Reactions in MIEC Membrane Reactors 315
9.1 Introduction of Catalytic Membrane Reactors 315
9.2 Types of Membrane Reactors 316
9.3 Partial Oxidation of Hydrocarbons for Syngas or Hydrogen Production 317
9.3.1 MIEC Membrane Reactors for Methane Conversion to Syngas 318
9.3.2 Membrane Materials 320
9.3.2.1 Co-based Perovskite Membranes with Improved Stability 321
9.3.2.2 Co-free Perovskite Membranes 323
9.3.2.3 Degradation Mechanism of Perovskite Membranes for Methane Conversion 325
9.3.2.4 Dual-Phase Membranes 331
9.3.3 Activation of the POM Reaction in MIEC Membrane Reactors 335
9.3.4 Mechanic Stability 340
9.3.5 MIEC Membrane Reactors for Fuel Conversion to Syngas or Hydrogen 342
9.4 Selective Oxidation of Hydrocarbons to Value-Added Products 343
9.4.1 Oxidation Coupling of Methane to Ethane and Ethylene 343
9.4.2 Oxidation Dehydrogenation of Light Alkanes 344
9.4.3 Other Reactions 346
9.5 Selective Removal of Oxygen from the Reaction System: Water Splitting for Hydrogen Production 346
9.5.1 Membrane Materials 348
9.5.1.1 Perovskite-Related Membranes 348
9.5.1.2 Dual-Phase Membranes 349
9.5.2 Stability Under High Oxygen Partial Pressure Gradient 350
9.5.3 Production of Ammonia and Liquid Fuel Synthesis Gas in One Membrane Reactor 351
References 353
Chapter 10: Progress on the Commercialization of MIEC Membrane Technology 359
10.1 Air Separation for Pure Oxygen Production 359
10.2 APCI´s Technology 361
10.2.1 Brief Overview of the Development of MIEC Membrane Technology 361
10.2.2 MIEC Membrane Module Design and Fabrication 365
10.2.3 Module Sealing 368
10.2.4 Module Performance 369
10.3 Aachen University´s Technology 372
References 374